Embryonic Development: Gastrulation and Organogenesis

Study Notes

The embryo undergoes gastrulation, where the blastula transforms into a gastrula
Three primary germ layers form:
1. Ectoderm: gives rise to skin, nervous system, and sensory organs
2. Mesoderm: forms muscles, bones, and internal organs
3. Endoderm: develops into lining of digestive system and respiratory tract
Gastrulation occurs through a process of invagination, where cells move inward to form a double-layered embryo

The three germ layers begin to differentiate and organize into specific tissues and organs
Neural tube formation:
- Ectoderm invaginates to form a neural groove
- Neural groove folds in to form a neural tube, which will develop into the brain and spinal cord
Heart formation:
- Mesoderm differentiates into cardiac tissue
- Heart tube forms and begins to divide into four chambers
Somite formation:
- Mesoderm segments into repeating blocks called somites
- Somites will develop into muscles, bones, and skin of the back

Eye development:
- Optic vesicles form from ectoderm
- Lens and retina develop from optic vesicles
Ear development:
- Otic placodes form from ectoderm
- Inner ear structures develop from otic placodes
Brain development:
- Neural tube differentiates into forebrain, midbrain, and hindbrain
- Brain structures begin to take shape, including cerebrum, cerebellum, and brainstem

During gastrulation, the blastula transforms into a gastrula, forming three primary germ layers: ectoderm, mesoderm, and endoderm.
Ectoderm gives rise to skin, nervous system, and sensory organs.
Mesoderm forms muscles, bones, and internal organs.
Endoderm develops into the lining of the digestive system and respiratory tract.
Gastrulation occurs through invagination, where cells move inward to form a double-layered embryo.

During organogenesis, the three germ layers differentiate and organize into specific tissues and organs.
Neural tube formation: ectoderm invaginates to form a neural groove, which folds in to form a neural tube, developing into the brain and spinal cord.
Heart formation: mesoderm differentiates into cardiac tissue, forming a heart tube that divides into four chambers.
Somite formation: mesoderm segments into repeating blocks called somites, developing into muscles, bones, and skin of the back.

Eye development: optic vesicles form from ectoderm, developing into the lens and retina.
Ear development: otic placodes form from ectoderm, developing into inner ear structures.
Brain development: the neural tube differentiates into forebrain, midbrain, and hindbrain, with brain structures taking shape, including the cerebrum, cerebellum, and brainstem.